Lesions of the anterior cruciate ligament (ACL) are the most common ligamentous injuries with an increasing incidence. 77% of ACL insufficient knees result in moderate to high physical limitations. Different surgical treatments have been described. ACL reconstruction with either a semitendinosus or patella tendon graft is regarded as the gold standard of operative therapy. Despite numerous studies representing good and excellent outcome after ACL reconstruction, a recent Meta-analysis of Biau et al. 2006 revealed that only 40% of patients gain full functional recovery.